engine wont start

[Jimbo31]

hello guys I have a bit of a question,

I am very much electrically challenged and have no idea what I'm doing. I took the entire bike apart to fix the engine and now that the engine is back in I have plugged everything in that comes from the engine. With the forks off I plugged the throttle, brake, clutch and even speedo in but when I put the battery on and turn the key the start button wont do anything and the engine doesnt start. The gas tank is off, all lights are not on just the basics because I just wanna see if the engine will turn over.

When I put the starter switch in to the on position I hear a click from a little box near the engine but still no starting (lights on the speedo are on (neutral and oil) but still nothing. Is there something I'm missing? I have used two different batteries and am charging one as I type this.

any help would be much appreciated thanks!

 

[arfstrom]

Hi Jimbo, without knowing what type of bike, it hard to guess. if its 82 an newer your safety relay may not register the kickstand position. if its 80-81 could be a ground issue, (okay, any year issue) older than that, could be the coils are not plugged in. or backwards. Starter electric bundle not fully seated.

good luck, insert music theme"These are a few of my favorite things" when the bike starts, when the kids behave ...

Tobie

 

[Jimbo31]

oh god sorry about that its a 1981 xs400 but i dont see a wire coming from the kickstand. What are these coils you speak of and is there a tricky ground wire i may be missing? particularly with the front forks because they are not attached.

 

[phate]

I would detach the starter motor's cable from the solenoid and manually touch it to the positive terminal on the battery. There might be a brief spark but make sure you touched the cable to the terminal to fully test it. If it works I would suspect solenoid problems or a discharged battery. Also there is a ground wire that goes from the engine case to the negative terimal of the battery may not be necassary but I would attach it anyways. Good luck and keep us posted

 

[arfstrom]

I was talking of the ignition coils, the spark plug wire plugs into it. Some people reattach em backwards. at first. When I was doing that last yea(/or the year before) I used a permanent marker to make same marks on both connectors.

Tobie

 

[Drewcifer]

yeah, go back to zero. Check coil wires for correct side first. then gas, air, spark. Assume nothing, work forward until you have spark on the correct side (TDC) at the right time. Without that it won't ever start.

 

[Lou Ranger]

I have no experience with this sort of thing on a bike, but once my car had a stuck starter motor because it had been installed with the drive teeth not lined up right.
Have you confirmed that everything that should turn can turn leaving only an electrical problem to look for?
If not, try loosening the plugs and verify that the engine can be turned over by hand.

 

[Jimbo31]

hey guys thanks for the help, a little update:

So I bridged the starter and it cranked so the starter doesnt have a problem are there any killswitches I dont know about that might need to be plugged in first before I could use the actual starter button? The wiring looks all properly plugged in except for any lights at the back and almost everything at the front except for the brake, clutch, and starter switch

 

[Scorpio1963]

Have you verified the engine will turn over by kickstart .There shouldnt be any kill switchs except for the on and off on the right side handle bar.Have you tryed looking into those connections?

 

[Drewcifer]

any progress?

 

[Jimbo31]

no, I havent really tried it lately. I heard something about a possible kick start switch? Yes the engine turns over no problem with the kick starter but i havent gotten it to fire yet (then again i just put the carbs on and there may not be enough gas when i tried)

 

[arfstrom]

Nope, no Kick start switch. How ever the switch with two "OFF's" does need to be in the On position. In my first post, I was eluding to the 82 has a "Kick STAND" safety relay. Since you have a 81, we don't have that relay. You do have 2 relays under the H tube, One of which is a safety relay, and the other is a relay that doesn't turn on the Headlight till the stator is working. and they are hard to tell apart, unless you have the wire diagram with you,

Yup, Safety relay has the Sky blue wire, the headlight relay has one white wire on the XS400 81 Special 4R4 model. I suspect if you have the H or G, model, it is going to be close to the same. I take it back, The G/ SG model doesn't have a Safety relay.

http://www.xs400.com/forum/showpost.php?p=78311&postcount=59 XS400SH model
http://www.xs400.com/forum/showpost.php?p=54633&postcount=17 XS400G/SG model

I found / figured this out in the Tech section, under Wire diagrams, that thread has expanded to 5 pages, since I last checked it out. If I looked harder, I might have found the one posting with color coded XS400 S/SG model. I know its there, I think that was some of us Frozen riders Do, is Modify things while we wait for the the weather to improve.
Tobie

 

[Jimbo31]

hey guys im working on it right now. I cleaned out the switch and now it turns the bike over but all it does is turn turn turn and POP and all the pressure comes out of the cylinders either through the carbs or exhaust. I dont think im getting a spark but im going to look right now

 

[Jimbo31]

spark plugs are fine, but it either back fires or front fires. smoke either comes through the carbs or smoke shoots through the pipes with a loud pop when I try to start it. I assume the timing is off any ideas?

 

[Scorpio1963]

Arfstrom

 In my first post, I was eluding to the 82 has a "Kick STAND" safety relay. Since you have a 81, we don't have that relay. You do have 2 relays under the H tube, One of which is a safety relay, and the other is a relay that doesn't turn on the Headlight till the stator is working. and they are hard to tell apart

Today while working on my bike I found these relay switches except my bike has only 1 and its an 82.I found the plug and a empty spot where a relay would be and I was going to ask what it is.So is it possible to unplug this relay and the bike will still start?Yes Im sure The Bike is an 82.

 

[arfstrom]

With out knowing the whole story about your bike, I am going have to let you do some google/forum searches, These issue pop up here all the time. The bikes if they are original, will have 3 serial numbers that match. then you validate it via our Tech knowledge of all important knowledge zone. (top of the page marked TECH) If all the numbers match, then most likely the bike has all the original stuff. If your unlucky, the PO has parted in/out all sorts of stuff, and making it hard for us to second guess your problems.

Backfiring, I had the problem while I was having a big issue with a float issue. (Holy floats) Seems one last in and out, fixed all that.

Kickstand safety, I know nothing. Good luck PS its on here, just look, (I love helping, but I know my limits) ((Most of the time))
Tobie

 

[16VGTIDave]

The coil wires may be reversed so they are firing on the exhaust stroke rather than compression stroke. Or the plug wires are on the wrong plugs, causing the same issue.

 

[Jimbo31]

after looking this up this is the solution ive come down to. I'm gunna try switching the coils next time for sure.

 

[Drewcifer]

Dave is correct. I said to check that above but might not have been clear enough in my explanation. With the tank on and the wires dangling it can sometimes be hard to tell which coil is connected to which wire, and the can get swapped. And we have ALL put the wires back backwards at least once in our career!

this sounds EXACTLY like what a nighthawk did to me when I accidentally reinstalled coils backwards. The fuel was combusting in the exhaust because it was sparking during the exhaust stroke.

Air, Gas Spark means correct amounts at the right time!

 

[XSLeo]

It's not the coils. Without the front end on the start button has no ground. Does the horn work? No ground on the handle bars and the starter button and the horn won't work.
Leo